A railcar generally provides a pair of side frames on each side having downwardly opening jaws. A bearing adapter is vertically moveable within the jaw and rests on a bearing mounted on a railcar axle carrying a wheel of the railcar. Typically, a bearing for a railcar axle fits around a journal at the end of the railcar axle where it is mounted between a backing ring assembly and an end cap.
The railcar adapter acts as a rigid connection between the bogie frame and the railcar axle. There is thus no possible movement between the railcar adapter and the bogie frame in case of relative movement between the bogie frame and the railcar axle. The guiding surfaces of the railcar adapter are thus rapidly deteriorated. Indeed, the twisting of the bogie frame generates high efforts on the guiding surface of the adapter and on the bearing.
Therefore, it is an object of the invention to reduce the efforts transmitted from the bogie frame to the adapter.
A solution to reduce those efforts is to harden the adapter. However, such solution is not satisfactory since it is expensive and has an impact on dimension and tolerances of the bearing seat and on the guiding areas of the adapter.